ActionsMedial Knee Anatomy


Primary valgus stability

- alone at 30o flexion


Secondary restraint to

- anterior translation

- to ER


Secondary medial stabilisers


Contribute in extension




- medial capsule 

- posterior oblique ligament

- medial meniscus




- pes anserinus

- SM


Hughston JBJSA 1976

- MCL resists 50% of applied force        

- anterior & posterior capsule 25%

- ACL & PCL 25% (PCL>ACL)        


Seebacher's 3 layers of medial knee


1.  Superficial layer

- deep fascia / fascia lata


2.  Middle layer

- patella retinaculum


3.  Deep layer

- MCL, OPL (oblique popliteal ligament), SM (semimembranosus), capsule




Medial Knee Anatomy


Superficial portion MCL

- triangular in shape

- origin medial epicondyle distal to adductor tubercle

- inserts proximal medial tibia

- deep to pes anserinus

- anterior margin free

- posteriorly blends with capsule and is attached to medial meniscus

- posterior to MCL is OPL


Deep MCL

- deep to MCL

- meniscofemoral and meniscotibial ligaments

- capsular thickening



- attaches to the posteromedial corner of the tibia

- just below the joint line

- important dynamic stabiliser


Oblique Popliteal Ligament


Thickening of posteromedial capsule

- extension of semimembranosus

- originates from adductor tubercle


3 insertions

- superficial arm from femur to tibia posterior to MCL, running over SM to blend with pes

- tibial arm attaches to medial meniscus then to proximal tibia

- deep arm is an extension from SM to posterior capsule


Pes anserinus


Runs superficial to MCL

- 3 components


Say Grace before Tea

- Sartorius

- Gracilis

- Semitendinosus


The saphenous nerve and small saphenous vein emerge between sartorius and gracilis


Mechanism of injury


Valgus force coupled with ER injures 

OPL as well as MCL


Site of Injury


MCL usually tears at femoral end

- laxity more likely at tibial end


Associated Injuries


1.  ACL 

- grade II MCL has a 70% association with ACL


2.  Meniscus

- most common with combined MCL & ACL injury

- lateral meniscus more common 3:1 with ACL tear 

- O'Donaghue triad rare

- Shellbourne 163 cases >50% had lateral meniscus tear




Discreet tenderness at femoral or tibial insertion of MCL


Tested in extension & 30° flexion


Remember to test both sides

- compare to contralateral side


Lax in extension

- tear to secondary constraint

- ACL / PCL / medial capsule




Grade 1 / Laxity in flexion 3-5mm


Indicates mild sprain of MCL

- up to 1/3 torn

- usually no laxity in extension


Grade 2 / Laxity in flexion 5-10mm


Indicates moderate sprain of MCL

- 1/3 to 2/3 torn

- usually no laxity in extension


Grade 3 / Laxity in flexion >10mm


Indicates complete disruption of MCL

- no endpoint


Usually lax in extension

- indicates disruption to secondary restraints


Also may have

- ACL laxity

- OPL instability / positive anterior draw in ER

- PCL laxity 




Usually normal in acute injury


Bony Avulsion


MCL Bony Avulsion


Pellegrini-Stieda Lesion 

- calcification at insertion of femoral MCL

- indicative of chronic injury

- can rarely be symptomatic

- requires excision of calcification +/- reconstruction MCL if needed


Pellegrini Steida Lesion






1.  Femoral injury


MRI Grade 3 Femoral Avulsion MCLMCL acute grade 3 Femur MRI


2.  Tibial avulsion

- can be flipped above pes

- will not heal

- will require surgery


3.  Midsubstance

- rare


MCL Midsubstance Tear MRI 1MCL Midsubstance Tear MRI 2




See thickening of ligament


MCL Chronic Femoral Thickening on MRIMCL Chronic Femoral Thickening




Will see lift off of the medial meniscus


Arthroscopic Lift off of medial meniscus in MCL injury




Non operative Management



- isolated injury

- no ACL / meniscal injury

- no displaced tibial avulsion




Delayed ACL reconstruction


Manage MCL non operatively as per below

- delayed ACL reconstruction if required


Zaffagnini et al JBJS Br 2011

- 3 year follow up of ACL reconstruction with grade II MCL treated nonop

- no impact on AP instability at 3 year follow up


Immediate ACL reconstruction


Halinen et al Am J Sports Med 2006

- RCT of acute ACL reconstruction in patients with grade 3 MCL

- operative v non operative management of MCL

- no difference in the two groups


Millett et al J Knee Surg 2004

- early ACL reconstruction with non operative management MCL in 18 patients

- at 2 year follow up no graft failure or valgus instability




Grade 1


Control pain & inflammation


- analgesia

- weight bear as tolerated

- ROM exercises

- muscle-strengthening exercises once FROM


Grade 2


As above plus hinge brace for 2 - 4 weeks

A.  Protect against valgus stress

B.  Full range if proximal MCL tear

C.  15° extension block if distal tear MCL or POL tear as well


Grade 3


- prevent full extension


6/52 in ROM hinged brace

- 30-60o for 2/52

- 30-90o for 2/52

- full range for 2/52




Marshall et al Clin Orthop 1978

- demonstrated equal results with operative v non operative treatment of MCL


Operative Management



- displaced tibial avulsion

- displaced bony femoral avulsion

- chronic MCL instability

- MCL instability after ACL reconstruction


Bony MCL Avulsion


Elevate VMO

- repair with staples


MCL Bony Avulsion IntraopMCL Bony Avulsion Intraop 2


MCL Bony Avulsion ORIF APMCL Bony Avulsion ORIF Lateral


Stener Lesion


MCL Stener Lesion


Chronic MCL reconstruction


1.  Distal MCL MCL Advancement

- if detached from tibia

- double row repair (as for rotator cuff) increases surface area for healing


Distal Tibial Advancement 1Distal Tibial Advancement 2


MCL Tibial AvulsionMCL Tibial Avulsion Double Row Repair


2.  Proximal MCL Advancement


Proximal MCL Advancemetn 1Proximal MCL Advancement 2Proximal MCL Advancement 3



- proximal laxity



A.  3 x figure 8 stitches to imbricate MCL and POL proximally

- tie over screw

- tighten MCL and POL


B.  Detach MCL

- 2 x distal suture anchors, pass sutures through tendon

- proximal staple


MCL Reconstruction APMCL Reconstruction Lateral


MCL Advancement APMCL Advancement Lateral


3.  Reconstruction of MCL and posteromedial complex (OPL / SM)


A.  Semitendinosus


MCL Reconstruction 2 Incision



- left attached distally

- re-routed more posteriorly on tibia around screw and soft tissue washer

- to medial epicondyle / isometric centre

- line of intersection of posterior femoral condyle and blumensaats

- insert wire and test isometricity in flexion / extension

- drill hole and fixate with RCI screw into blind loop of tendon

- return to tibia posteriorly to reconstruct OPL / secure with anchors and supplementary screw post


MCL Isometric PointMCL Reconstruction Tibial Screw Post


Lind et al Am J Sports Med 2009

- 50 patients followed up for minimum 2 years

- isolated instability / ACL and MCL / multiligament knee

- 98% had medial stability of normal or nearly normal


Kim et al JBJS Br 2006

- semitendinosus left attached distally

- reconstruction of MCL and OPL

- medial joint line opening within 2 mm in 22/24 knees


B.  Allograft

- doubled tibialis anterior

- tendoachilles allograft - bone block in medial femoral epicondyle


Marx et al CORR 2012

- 14 cases treated with tendoachilles

- good results in all cases


4.  Hughston Procedure



- advance femoral attachment of MCL

- advance femoral attachment of OPL

- stretch OPL anteriorly onto MCL

- reef SM forward to decrease slack


Surgical Approach to Medial Knee



- knee flexed to 90o, over bolster

- tourniquet

- sandbag under hip



- hockey stick medial incision

- halfway between borders of tibia

- extends proximally to adductor tubercle

- distally to pes


Superficial dissection

- protect the saphenous nerve and small saphenous vein

- emerges from between sartorius and gracilis

- divide fascia over pes, reflect downwards

- divide medial patella retinaculum from VMO down to the pes


Deep dissection

- expose MCL running down to tibia under pes

- oblique popliteal ligament and SM are posterior to it

- can expose posterior capsule by carefully reflecting medial gastrocnemius posteriorly

- enter to joint if needed between posterior border of MCL and OPL

- identify proximal MCL attachment by elevating V medialis